# Copyright 2014-2018 The PySCF Developers. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import numpy


try:
  from scipy.special import factorial
except:
  from scipy.misc import factorial
  
sgn = numpy.array([ 1.0-1.0 * (i % 2)*2 for i in range(171)], dtype='float64')
fact = numpy.array([ factorial(i, exact=True) for i in range(171)], dtype='float64')
onedivsqrt4pi = 1.0/numpy.sqrt(4.0*numpy.pi)
rttwo=numpy.sqrt(2.0)
